1. Field of the Invention
The present invention generally relates to locking cover plates for open ends of plumbing components. More specifically, the present invention relates to protective locking cover plates for fire retardant sprinkler systems having a stortz-type coupling arrangement.
2. Related Art
In fire retardant automatic sprinkler systems having multiple sprinkler heads, the standing water supply often is insufficient to maintain optimum operating water pressure when there are several sprinkler heads in simultaneous use. Accordingly, the National Fire Protection Association Code requires a connection, such as a stand pipe connection, through which a fire department can pump water into the sprinkler system. The pumped water is used to charge or recharge the sprinkler system as desired.
Where such stand pipe connections are provided, upon arrival of fire department personnel, an auxiliary source of water such as a hose supplied with water from a fire truck pump can be connected to the sprinkler system. Increasingly, stortz-type connectors are used to facilitate the connection. Stortz-type connectors provide a particularly advantageous manner of rapidly connecting and disconnecting hoses to a stand pipe, for instance. The stortz-type connector generally features a pair of arcuate slots with enlarged insertion openings. The slots are formed on a circular flange. The enlarged insertion openings receive mounting pins or feet from a mating fitting. The pins are inserted into the slots and rotated about a quarter-turn relative to the stationary fitting to couple the two components together.
The National Fire Protection Association Code also specifies that such hose connections shall be equipped with caps, plugs or cover plates. Because the hose connections are in public locations, which can be unsecured, the cover plates desirably reduce the likelihood of tampering by passersby, vandals or arsonists. Thus, the cover plates cover the auxiliary water inlet to prevent the inadvertent or malicious introduction of trash or other debris that might clog the sprinkler system during operation of the sprinkler system in an emergency.
Several types of caps, plugs and cover plates have heretofore been provided to cover the connection. These caps, plugs or plates are provided to protect the integrity or operability of the sprinkler system. One such arrangement includes a plate with inwardly extending pins. The cover plate mates with the stortz fitting and the cover plate is secured by sliding the pins through the slots and rotating the cover plate. The cover plate must be capable of quick removal in case of an emergency. Thus, the cover plate generally is not locked to the fitting and has not been suitably secured against unauthorized removal. As a result, the plate is susceptible to unauthorized removal, theft and vandalism.
Accordingly, a locking cover plate is desired for a stand pipe having a stortz fitting. The plate should be capable of easy-removal by authorized personnel while being difficult to remove if unauthorized. Additionally, the plate preferably provides visual confirmation of whether or not the lock has been engaged. Furthermore, the plate preferably is substantially weather-impervious and capable of removal under extreme climatic and environmental conditions by emergency personnel that are under high anxiety and time pressure.
One feature of the present invention takes advantage of characteristics of a bolt featuring a specially designed bolt head. The bolt is commonly used in applications that involve securing two components together and reducing the likelihood of removal. In addition, the bolt is difficult to damage due to its construction. In use, the bolt is tightened with a special driver that mates with the bolt head. The driver preferably is not readily available on the market. The pattern on the bolt head makes difficult generating high degrees of torque on the bolt. Accordingly, generating sufficient torque to remove the bolt generally requires the special driver. This feature is combined with an interference member lock device (i.e., a bayonet-type of lock). Typical bayonet-type locks feature a keyed entry such that a typical lock cylinder and key arrangement is used to open and close the lock. The cylinder and key arrangement is susceptible to vandalism or damage. Due to the particular environments and industries in which the present invention generally will be used, a combination of these two components was developed. The combination results in an interfering lock that is selectively deployed through turning the bolt. The bolt, however, can be tightened to generate a locking friction force that is difficult to overcome without the corresponding driver and the bolt is difficult to damage or destroy.
Thus, one aspect of the present invention involves a locking cover plate for an open pipe end having a stortz-type fitting. The cover plate comprises a housing having a front surface and a generally cylindrical side surface. An actuator assembly is substantially contained within the housing. The actuator assembly comprises a drive bolt extending rearward from the front of the housing. A cam plate is connected to the drive bolt and a torque limiting assembly selectively couples the cam plate to the drive bolt. The cam plate is capable of rotating relative to the drive bolt when coupled by the torque limiting assembly to the drive bolt and the cam plate is capable of translating relative to the bolt when not coupled by the torque limiting assembly to the drive bolt. A latch bar is connected to the cam plate and is disposed for translation generally normal to an axis that extends through the drive bolt. An indicator assembly is connected to the latch bar.
Another aspect of the present invention involves a protective cover plate for a stortz connection of a piping system. The cover plate comprises a front plate and a stortz fitting extending rearward from the front plate. A sliding plate locking mechanism is disposed rearward of the front plate and is adapted to engage a concealed portion of the piping system when the cover plate is assembled to the piping system.
A further aspect of the present invention involves a method of installing a cover plate to a piping system having a stortz fitting. The method comprises inserting the cover plate into the stortz fitting, rotating the cover plate to secure the cover plate to the stortz fitting, turning a cam plate, translating a latch bar, indicating a movement of the latch bar, and loading an actuator assembly with a tamper-resistant torsion load.
Another aspect of the present invention involves a method of removing a cover plate from a piping system having a stortz fitting. The method comprises unloading a tamper-resistant torsion load, rotating a cam plate, translating a latch bar, indicating movement of the latch bar and removing the cover plate.